Method for the manufacture and treatment of polyamide fibers



Jan. 27, 1959 T. s. MAYNER 2,871,090

METHOD FOR THE MANUFACTURE AND TREATMENT 0F POLYAMIDE FIBERS Filed' June 29, 1955 .1N V EN TOR.

THOMAS S. MAYNER ,5mg a @E e@ ATZ'ORVEY United States 'Patent O METHOD Fon THE MANUFACTURE AND TREAT- MENT oF PoLrAMIDE FnsERs l Thomas S. Mayner, Chagrin Falls, Ohio, assigner to Industrial Rayon Corporation, Cleveland, Ghio, a corporation of Delaware Application .lune 2,9, 1953, Serial No. 364,881

3 Claims. (Cl. 8-151.1)

This invention relates to the production of synthetic polyamide polymeric bers, and more particularly to an improved method for the manufacture and treatment of such fibers melt spun from polycaproamide polymers.

In the condensation polymerization of e-amino caproic acid or e-caprolactam (e-amino caprolactam) itis known that the reaction does not proceed to completion and that in the end of the polymerization reaction a state of equilibrium exists between the polymer and monomeric or dimeric lactam wherein the polymerization product contains up to about l percent of the unpolymerized lactam. A

It is also known that the presence of such lactams in extruded, shaped articles, hereinafter referred to as thread or yarn, present spinning and processing difficulties. Thus, it may be necessary to interrupt a continuous process operating at increased rates with slow and expensive washing steps after extrusion. Also, there is a vloss of yarn strength caused by the handling of such lactamcontaining threads, etc. during the transfer of such freshly spun yarns over yarn advancing devices, guides, and during subsequent stretching and rewinding operations.

lt has been proposed that polyamide fiber containing excessive lactam be coated with a lubricant so as to prevent tilament breakage as lthe yarn passes over various yarn handling devices during subsequent processing steps, e. g., stretching, packaging, unwinding, etc. Another proposal is to remove excessive lactamprior to extrusion. This entails `additional and expensive equipment that is not entirely satisfactory, unless extreme precautionary measures are taken in removing sutcient quantities of the lactam. lt is preferred to extrude the lactamfcontaining polymer to form the fiber and then remove `ex? ccssive lactam by a simple and efficient washing means that can be operated at increased speeds rendering the yarn in a condition suitable for after-treatment in a continuous manner.

In accordance with the present invention the extruded,v

polycaproamide thread containing lactam is subjected to a wash, then stretched, and then collected onto a suitable spool or bobbin. The excessive or undesirable quantities of lactam are Washed and scrubbed oif the yarn while it is stored in a plurality of generally helical turns which are continually subjected -to the action of water.

ln practicing this invention the lactam-containing yarn is advantageously stored in the form of an elongated helix supported by spaced, positively-driven feed rolls operated at over 200 meters per minute. A spray of a washing liquid such as water at room temperatures and preferably elevated temperatures, is applied to the helix for over generally the entire length and width of the helix, and it is applied and maintained thereon by a exible blanket positioned to partly envelop at least one of the feed rolls and contacting at least one entire side of the helix to about the point of contact of the thread turns on the other of said feed rolls. The blanket may be of any desirable material having exible characteristics enabling it to conform to the helix shape.

It can be a sheet, or V 2,871,090 Patented Jain. 2,7, 1959 rice 2- a iilm, either woven or knitted, of rayon, nylon, orlon, etc. Of course where a corrosive liquid is used the blanket materials have to be selected to withstand such a liquid. Preferably, the helix can be substantially enveloped in a like manner on its other side. Thus, any applied liquid is quickly and eliciently spread onto the blanket and as a result applied onto the thread turns forming the helix for over substantially the length of their contact with the blanket. There occurs a continued washing of the thread turns and, of course, a continued lubrication of the blanket and of the thread turns by the wash liquid scrubbing out the lactam monomers. This In the drawing Figure l represents in schematic ar rangement a melt-spinning apparatus;

Figure 2, taken across line 2-2 of Figure l, represents:

the thread washing section of the apparatus; and

Figure 3, taken across line 3-3 of the washing section of Figure l, represents the same washing sectionv of Figure l but from an opposite side.

In the drawing there is shown a portion of a meltspinning funnel 10 of a melt spinning apparatus (not shown) from which continuously emerges a thread 11 being lead into a liquid treating .compartment 12 through a guide 13 positioned in the wall of the compartment to a thread-advancing and thread-storing reel. The reel shown is formed of two positively driven feed rolls 15 and 16 spaced from each other and arranged on axes that are canted to each other so `as to effect an advance of the yarn 11 in the forni of an elongated helix having a plurality of turns.

There is positioned into contact with the yarn helix a liquid spreading blanket 18. Y The blanket "is mounted and secured to a bar 19. The bar 19 supporting the blanket 18, is positioned relative to the feed roll 15 so as to substantially enshroud the roll, and the blanket -18 extends along the thread helix and in contact with it for its entire unsupported length between the two rolls 15 and 16. The liquid spreading blanket 18 extends to the feed roll 16 to about'the point where the helix and the feed roll come in contact. Since the feed roll 15 is canted relative to the feed roll 16, the thread turns change in direction slightly, and to extend the liquid blanket 18 beyond the direction change would effect a slight distortion of the blanket with, as a result, an uneven spread of a liquid. The anchored extension of the .blanket :1S over and beyond a feed roll 15 tends to pick up thrown liquid by the feed roll which is then returned by the blanket 18 to the thread helix.

A treating liquid supply 20 spills a wash liquid such as hot water over a width of the helix equal to about the width of the blankets 18 or 25. Any stream, however, applied to the reel 15, 16 would be spread over the entire blanket contacting area in an even iiow each thread turn being subjected substantially equally to a washing action. Any excess wash, or wash centrifugally thrown, is drained off through an opening 22 positioned in the base of the compartment 12.

In order to provide for a more fully effective washing treatment of the yarn 11 containing lactam monomer which is to be washed out there is provided about the thread-advancing reel formed by the relationship of the feed rolls 15 and 16 a second blanket 25 positioned opposite the first blanket 13 on the other side of the thread helix. The second blanket 2S is maintained in position by being anchored or fastened to fixed rod 26 located so as to effect a partial enshrouding of the lower feed roll 16, and it extends upwardly along the helix to about the contact point of the threadhelix and the feed roll 15. The partial enshrouding of feed rolls 15 and 16 by the blankets 18 and 25, as stated, catches centrifugally flung washing liquids by the uncovered areas of the helix and returns such liquids to blankets 1S, 25 which reapply them to the thread helix. This arrangement enables the use of high rotative speeds with a minimum of turbulence, throwing-off and quantities of washing liquids used. The wetted blankets 18 and 2S, being of flexible and resilient natures, cling and conform to the helix sides, applying and spreading a treating liquid evenly over the entire area covered so that each thread turn has an effective treatment from its initial formation on the reel to the point of take-off. A length of thread is thus effectively washed and scoured for over a substantial period dependent upon the width and size of the helix found to be necessary to provide a suiicient washing treatment.

In the event that one such washing treatment is found not to be sufficient and that it is not desired to expand and enlarge the first thread-storing, thread-advancing reel, then two smaller reels can be effectively utilized. Yarn or thread of the iirst reel is led to a second reel for a further wash treatment, or for some other treatment that may be required. The second reel can be positioned in the same compartment 12 and desirably in a section formed by the partition 28. The thread 11 is lead through a guide 29 in the partition 28 Onto the second reel formed of two spaced, canted positively driven feed rolls 30 and 31. The second reel is also partly enshrouded by the film applying and spreading, blankets 32 and 34 being anchored and supported by the members 33 and 35 respectively. A second liquid supply 36 is provided adjacent the feed roll 34) and sprays or spills a treating liquid onto the feed roll 30 which liquid is then spread over the entire thread helix by the first blanket 32, and kept thereon by the second blanket 34.

Each section of the compartment 12 is drained through exhaust openings 22 and 37 respectively. The yarn 11 leaves the compartment 12 through a guide 39 in the base of the compartment being drawn therethrough by godet 40, thence it is led to godet 41, godet 42, through guide 43 onto a collecting bobbin 44 being rotated by the roller 45. A stretch of the thread 11 is effected between and by the godets 41 and 42, the stretch being in the' nature of about 10 times, and thereafter the yarn is collected on the bobbin 44 while still maintaining some moisture retained from its liquid treatment.

.It has been found that water at room temperature is elfective'in washing out the lactam monomers. Howe ever, water at elevated temperatures is more effective and less quantities of it can be used. Water at temperatures of about boiling is particularly effective in washing out lthe monomer which should be reduced to about less than 4% in the linal thread.

Thread-advancing reels of the spaced roller type advantageously provide for an elongated helix having, generally, no limitation as to size. A disadvantage, however, has been that a full and eicient and continuous scrubbing of a helix could not be had except about the feed rolls themselves, the unsupported -helix sections between the rollers seldom being capable of an equivalent treatment similar to the helix sections passing over the rollers. Complete immersion in a wash bath -is inconvenient and tends to splashing, lack of control of helix pitch, excessive use of a wash liquid, and of handling.

A flexible blanket of the nature described has the property, upon being wetted, to cling or adhere to the thread turns. Being exible it will undulate with the helix, as well as tend to compact or draw the turns to its wetted surface, each turn being'subjected substantially equally to a wash. Such a blanket forms with a double-roller type reel an eicient, simple and a fast washing apparatus particularly for uses of the nature herein described.

I claim:

1. The method for washing out excess amounts of Water solubles from filaments, threads and yarns of polycaproamide polymers, comprising; forming of said lilaments, threads and yarns an elongated helix along its transverse axis having unsupported sections; advancing said helix through a wash treating stage; and while. in said wash stage frictionally wet brushing said helix including at least about the entire portion of an unsupported elongated section.

2. The method described in claim 1 where each unsupported helix section is included in the frictional Wet brushing treatment.

3. The method described in claim l in which the helix is advanced at over 200 meters per minute and the wash liquid temperature is that of about boiling.

References Cited in the le of this patent l UNITED STATES PATENTS 2,303,274 Herrstrom et al Nov. 24, 1942 2,509,741 Miles May 30, 1950 2,513,381 Truitt July 4, 1950 2,562,199 McLellan et al. July 3l, 1951 2,593,555 Guy Apr. 22, 1952 OTHER REFERENCES German :Plastics Practice, De Bell et al., Mass., 1946, p. 290. 

1. THE METHOD FOR WASHING OUT EXCESS AMOUNT OF WATER SOLUBLES FROM FILAMENTS, THREADS AND YARNS OF POLYCAPROAMIDE POLYMERS, COMPRISING; FORMING OF SAID FILAMENTS, THREADS AND YARNS AN ELONGATED HELIX ALONG ITS TRANSVERSE AXIS HAVING UNSUPORTED SECTIONS; ADVANCING SAID HELIX THROUGH A WASH TREATING STAGE; AND WHILE IN SAID WASH STAGE FRICTIONALLY WET BRUSHING SAID HELIX INCLUDING AT LEAST ABOUT THE ENTIRE PORTION OF AN UNSUPPORTED ELONGATED SECTION. 